Numerical investigation of multiphase transport model for hot-air drying of food

Abstract

Drying is widely used to prevent microbial spoilage by evaporating the determined amount of liquid in the food sample. In order to reduce energy consumption and increase food flavor quality, modeling the drying process is crucial. In the literature, different approaches are used for investigation of drying characteristic. Among these approaches, the porous media approach have complex phenomena. Molecular diffusion for gases (water vapor and air), capillary diffusion for liquid (water), and convection mechanisms (Darcy flow) were used in drying model in porous media. In this study, firstly, the effect of shrinkage on drying of porous media was investigated. Non-linear partial differential equations for air and food material in the drying problem were solved numerically for non-steady state condition. The shrinkage effect in the drying process was studied by using the ALE (Arbitrary Lagrangian Eulerian) method. In this study, air velocities of 0.5, 0.8 and 1 m s-1, air temperatures of 40, 50 and 60 °C and the geometric forms of rectangular, cylindrical and square were selected for hot air drying process. The fastest drying was obtained at square shape food at the air temperature of 60 °C and the air velocity of 0.5 m s-1. The analysis result showed that the air velocity and temperature have effect on the drying.